Compact excavators: 1.5 to 2 metric tons
| June 12, 2007 |
There was a time when American contractors looked on compact excavators with suspicion. To an older generation that cut its teeth on big iron, compact equipment – compact excavators especially – seemed like toys.
Compact equipment manufacturers will tell you that attitude has largely passed, and the numbers reflect that: This year, according to Equipment World’s 2003 Spec Guide, the 1.5- to 2-metric-ton class of compact excavators features 12 all-new models, with five new manufacturers entering the market.
But there are still skeptics out there. Take David Long Jr., who co-owns Fine Grade Construction, Ocoee, Florida, with his father, David Sr. The Longs do site prep work including light land-clearing and grade work as well as putting down residential pads. “We work in tight, confined areas,” Long explains. In many cases, the Longs and their crew were using a shovel to fill in footings.
About two years ago, Long first told his father they needed to add a compact excavator to their equipment fleet. “We’d traditionally been using backhoes,” he explains, “but they just couldn’t get into many of the places we found ourselves working.”
But the elder Long was resistant. “I don’t think Dad was worried about productivity or durability from a compact machine,” Long says. “Initially he was worried the compact excavator would slow us down because it wouldn’t be able to cover ground the way a backhoe does.”
The debate raged on for months until early this year when David and his father compromised. “He agreed that we’d get a compact excavator on the provision that we coupled it with a compact rubber track loader,” Long says. “He thought that combination would give us the speed and flexibility we were used to.”
In July, the Longs added a Komatsu PC15 MRX and an ASV RC30 track loader to their fleet and immediately saw their productivity skyrocket. “I just love this little excavator,” Long says. “We use it constantly. I’ve had it two months, and we’ve already put 230 hours on it.”
David’s dad is sold as well. “He told me at first that he thought we’d use the track loader more than the compact excavator,” Long says. “But that’s not been the case. Both machines are getting pretty equal time. We’re working four times faster than we used to, with three less men. The compact excavator saves me from having to do so much manual labor. It’s speeded filling stem walls in areas so tight you can’t get a skid steer into. We used to use a wheel loader – we’d dump a load of dirt in there and then spread it around with shovels and then run a hand-held vibratory compactor over the dirt. Now we dump the dirt in there and spread it with our PC15. And we’ve gotten rid of the small compactor altogether since I can simply compact the dirt with the excavator bucket.”
Using the excavator’s blade properly can help stabilize an excavator when digging or lifting.
Size follows function when matching excavators, skid steers
Fine Grade’s applications and experiences with its compact excavator are the norm for compact excavators in the 1.5- to 2-metric-ton class. Many models in this class feature zero-tailswing designs and retractable undercarriages that allow them to excel in tight working conditions. Even without those features, their small size and high breakout forces (relatively speaking) give them high productivity in tight surroundings.
“Most machines in this class have breakout forces ranging from 2,000 to 4,000 pounds on the bucket,” says Mike Ross, product marketing manager, Takeuchi. “That’s plenty for a guy who needs to do small machine type work like landscapers, utility contractors repairing gas and water lines or concrete guys who need to dig footings.”
Like the Longs, many contractors opt to run skid-steer or compact rubber-track loaders in tandem with their compact excavators. George Chaney, product manager, JCB, says that’s because the two units complement each other beautifully. “Price-wise, contractors can run a skid steer or a small track loader along with a small excavator for the same price they would pay to buy a larger backhoe,” he notes. “And they can really double or even triple their production at the same time since the two machines’ strengths mesh together so well. One operator can be digging, while the other can be hauling spoil away simultaneously. And once the actual digging work is complete, the skid steer can come in and quickly fill the trench. ”
The size skid steer to match a 1.5- to 2-metric-ton excavator is largely driven by application. Since most contractors purchase compact excavators to work in confined conditions, it logically follows that their skid steer of choice would be a small machine as well. “I would probably match a 1,350-pound to 1,550-pound skid steer with these compact excavators,” Chaney says. “Bigger skid steers are more powerful and let you move more material in a shorter length of time, but they’re also wider and heavier – which can be a drawback in many compact applications.”
The smaller units also are easy to transport, making them more cost effective to own and operate. “A compact hydraulic excavator and skid-steer loader both can easily fit on a trailer that can be towed by a pickup truck,” says Kevin Ingall, North American compact products manager, Caterpillar. “The cost of conducting business is less with these smaller machines because owners don’t have to purchase a large trailer or large truck to transport them. But they can still get the maximum versatility out of them.”
Trenchless applications benefit from compact excavators as well
Although skid-steer loaders garner the most attention working with compact excavators, other machines benefit from being paired with them as well. Ditch Witch is a new player in the compact excavator market and according to Mike Lumbers, product manager, that’s because compact excavators in this class work extremely well with two of its mainstays: directional drill rigs and trenchers. “Trenchless technology is all about disturbing as little of the environment as possible,” Lumbers says. “Compact excavators in the 1.5- to 2-metric-ton class typically put approximately 4 pounds per square inch of track pressure on turf, so they’re extremely friendly to lawns and landscaped areas. They can be used to open up drilling pits, and their ability to change attachments means you can swap to different buckets or small breakers if you hit rock or different soil types as you dig down. Another advantage is that a compact excavator can help your crews position different downhole tools in the pit, and of course they’re great at cleanup work at the end of the job.”
In a similar vein, Lumbers notes that compact excavators can also effectively complement trenchers. “They’re great because they can dig utility hookup pits as efficiently as a backhoe can. They’re cheaper to operate than a backhoe and can still engage in jackhammering and limited material handling.”
Make sure to spec a bi-directional flow hydrauilc system if you’re planning on using hammers and breakers with a compact excavator.
Blade placement, proper bucket work can easily enhance productivity
Gauging compact excavator productivity is usually a measurement of time. Because of the nature of the work they do, the tracking methods used in high production earthmoving or material handling work do not apply. Although you can use bucket capacities and time to track the volume of material your machine excavates in a given period, most contractors simply measure the total time taken to finish a job, compared to similar jobs they’ve completed in the past.
To this end, the ability to work quickly and effectively on a compact excavator is crucial. But that doesn’t mean ripping and tearing up the earth, says Chaney. “Many operators try to work too fast,” he explains. “But many times you’re better off slowing down a little bit. Decrease your engine rpms and make an effort to be fluid and smooth on the controls. Less experienced operators will end up rocking the excavator back and forth because they’re going so fast, and they’re actually losing time when they are doing that. Strive for consistent operation of the machine.”
Also remember to maintain a parallel bucket towplate to the ground when the bucket is raised all the way up. “If it’s not,” Chaney says, “you’re going to spill material out. If you raise it to dump into a truck and half the bucket spills out because you didn’t maintain parallel geometry, that’s a direct loss of productivity. If you follow those procedures, you’ll put less stress on the machine, spill less material and enhance your productivity greatly.”
Keith Rohrbacker, product manager, Kubota Tractor, says he sees many contractors lose productivity because of unstable machines. “Remember that a compact excavator does not have a wide footprint like a full-size machine does. So when you’re working on the site, you want to make sure they’re positioned so that they’re as stable as possible. Many machines in this class now have expandable tracks to help them fit into confined spaces. But those tracks need to be fully expanded when you’re getting ready to dig.”
Using the excavator’s blade properly can help stabilize an excavator when digging or lifting. But, Lumbers says, there’s more to blade positioning than simply lowering it to the ground. “Always make sure that you have your blade positioned in the proper area of the machine (front or back) whichever suits the type of digging or lifting you’re doing at the time,” he says. “If you’re digging in front of the machine, lower the blade in back and you’ll be able to put more downforce on the unit without lifting the tracks. And if you’re lifting something, put the blade down in the front of the machine to give you more stability.”
Simple tricks extend track life
Most compact excavators in the United States are sold with rubber tracks, which cause little or no ground damage to lawns or sensitive soils. A smaller percentage of machines (around 10 percent) are fitted with steel tracks, which optimize the undercarriage for use in harsh conditions with rock, concrete or debris-strewn areas.
In good operating conditions with a knowledgeable operator, most rubber tracks will last around two years, manufacturers say. But rubber tracks are simply not as durable as steel tracks. As such, they demand a little extra attention and care when the machine is in use. “Contractors need to watch track tension,” Lumbers says. “That’s the most important thing. If one is too loose, and you’re on a side slope, you can easily throw a track – and they’re no fun to put on in the field.”
“If you’re running the machine and you hear a little bit of a popping noise, that’s a sign that you need to adjust the track,” Chaney adds. “Every now and then you should raise the machine up and check how much sag you have in the track. And remember that you can tighten the tracks too much, which could result in unwanted wear on your rollers and idlers.”
“Don’t get will-fit tracks,” Ross urges. “I know they’re cheaper. But although they’re engineered with specifications very close to the original tracks, a lot of times the spacing in between the mandrils is off. And that’s going to cause those tracks to wear out faster, but it can also accelerate wear on the sprockets and rollers faster than the original tracks would. So you might save money up front when you replace your original tracks with will-fit versions, but you’re probably only going to get about half the life out of them, leading to premature undercarriage maintenance on the machine. They also tend to get thrown more often when you’re working in tight areas, and that’s downtime you don’t need.”
Finally, limit your machine’s exposure to Mother Nature if you want to extend track life, says John Morris, product manger, Thomas Equipment. “Long term track exposure to sunlight and rain can prematurely age rubber tracks,” he says. “If your machine is not going to be used for an extended period of time, cover the tracks or store the unit indoors.”
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